太仓—南通河段滩槽水沙交换及其演变关联性研究

Study on water-sediment exchange and its evolution correlation in shoal and deep groove of the Taicang-Nantong reach

依托长江南京以下深水航道建设工程,利用工程河段实测水文、地形资料,研究了通州沙和白茆沙河段局部滩槽水沙交换和河床演变的特征和关联效应,同时根据通州沙河段水沙交换时空分布特征确定了一期工程潜堤工程范围和各堤段高程。通过分析认为:在通州沙—白茆沙粉细砂底质为主的分汊感潮河段,滩槽沙量交换主要通过悬沙搬运实现,而潮流(尤其是落潮流)是掀沙、输沙和引起滩槽水流和悬沙交换的主要动力,其中,落潮流引起的水沙交换是塑造和改变局部滩槽形态和影响局部深槽稳定的重要因素。考虑到通州沙河段弯道水流对滩面的冲刷,在潜堤左缘布置丁坝群对滩面进行守护。

Depending on the deep water channel construction projects of the Yangtze River below Nanjing ,us-ing the measured hydrologic and topographic data,water and sediment exchange of the local beach groove,charac-teristics,associated effects of the bed evolution in the Tongzhousha and Baimaosha were studied. Meanwhile,ac-cording to the characters of time and space distribution of water and sediment exchange in the Tongzhousha ,sub-merged breakwater project scope and elevation of the first phase construction were determined. By the analysis：in Tongzhousha and Baimaosha which are branching tidal rivers with silty sand substrate,beach groove sediment ex-change is through the transportation of the suspended sediment,and trend （especially the ebb tide） is the main en-gine to lift,transport and exchange flow and suspended sediment of the beach groove. Water-sediment exchange caused by ebb current is the important factor shaping and changing local beach groove form and influencing the lo-cal stability of deep groove. Considering the scouring on the beach surface by the flow in Tongzhousha ,the dikes are layout in the left of submerged breakwater to protect the beach.